RHS Level 2 Certificate Year 1

Week 13 – Propagation by seed in practice

Learning outcomes

1.1 Describe how conditions for successful germination can be achieved in a protected environment.

1.2 Describe the sowing and aftercare of a range of seed types sown in containers.

1.3 Describe how the conditions for successful germination can be achieved in the open.

1.4 Describe the sowing and aftercare of a range of seed types sown outdoors.

Seed propagation in a protected environment

Control of the environment means that the germination conditions can be optimised

Important factors in this control are the choice of growing medium, water supply, use of a propagator or heat pad, mist bench use and cultural hygiene.

Practical steps to control germination environment

Use of sterile, moisture retentive, free draining seed compost

Allows oxygen to enter the soil whilst holding water. Sterile compost reduces the risk of ‘damping off’ diseases.

Supply of clean water – not rain water

Reduces the risk of ‘damping off’

Use of heated propagator or heat pad

To allow soil temperature to be controlled

Light – use vermiculite or compost to cover seeds unless they need light to germinate.

To provide the light conditions needed to germinate.

Cultural hygiene A basic requirement of any propagation

Equipment

Containers – seed trays, modular trays, seed pans, Jiffy 7’s, root trainers.

Propagator – may be a simple plastic cover for a seed tray or a more sophisticated heated unit. Conserves humidity and temperature.

Heat pad – thermostatically controlled and placed under the seed tray.

Mist bench – commercial use, provides heating and misting.

Sowing seeds in a modular tray

Used for those plants which resent root disturbance

No need to prick out so less labour intensive Takes up more space for fewer plants Unlike seed trays they tend not to be re-

useable.

Pricking out

Required for seeds that have been grown in a seed tray.

Moves the seedlings from the seed tray into individual modules or pots to grow on.

Requires a degree of care and skill. Must be done at the right stage of growth or

the seedlings will become crowded and ‘leggy’ and there is the risk of fungal disease.

Seed propagation outdoors

Used for hardy annuals, hardy perennials and many vegetables.

Cultivation – the aim is to produce a fine tilth For ornamentals unlikely to need additional fertilizer Use of the Stale Seed Bed technique to reduce

competition from weeds Sow either broadcast or in drills – the latter makes it

easier to see which are weed seedlings. Keep watered and weeded, thin out to final spacing,

provide support and dead head ornamentals as the season progresses to prolong the display

Plant examples

Hardy annuals usually sown direct into the ground – Papaver rhoeas ‘Shirley Series’, Clarkia amoena, Centaurea cyanus (Cornflower).

Biennials often direct sown – Verbascum olympicum, Digitalis purpurea, Myosotis sylvatica.

Learning outcomes

1.1 Describe how conditions for successful germination can be achieved in a protected environment.

1.2 Describe the sowing and aftercare of a range of seed types sown in containers.

1.3 Describe how the conditions for successful germination can be achieved in the open.

1.4 Describe the sowing and aftercare of a range of seed types sown outdoors.